The intervention is completed. All ports are UP and all HG are up in the monitoring.

The origin of the problem:
2 days ago we updated the software on some HG switches. tonight ,suddenly the switch said "servers' ports are down."
we first downgranded the software version from 5.2.1b to 5.2.1 because we had yesterday the first signals that b has problems.
finally we had to downgrade it to 5.1.3 and only then all problems has gone.

This is an unusual problem due to software bugs in network equipment that we are using. it is rare, very rare, but it happens.

We are sorry for the trouble.

Affected customers will have the right to 1 free month since the SLA has largely exploded.